1. Field of the Invention
This invention relates in general to certain new and useful improvements in structural systems, and more particularly, to space frame structural systems which utilize nodal connectors comprised of a plurality of substantially identically sized and shaped, mutually perpendicular, interfitted plates.
2. Brief Description of the Prior Art
The prior art is replete with a variety of structural systems using various types of structural nodes or connectors and various types of struts or beams which extend between and connect the structural nodes. One of the principle problems attendant to these various structural systems utilizing struts and the associated connecting nodes is the fact that there is no universality in the nodes or in the struts. Thus, substitution of one type of strut for another or substitution of one type of node for another in a structural system is not possible. Further, there is no universality in the means for connecting the struts to the nodes.
A further substantial problem in connection with the prior art structural systems was the fact that each structural node was comprised of a plurality of differently sized and differently shaped plates. This not only increased the cost of manufacture, but also substantially increased the difficulty in assembly.
Another significant problem with the prior art struts and structural nodal connectors is the fact that very specialized types of mechanical fasteners were required to connect the struts to the connectors. The mere fact that connectors were required substantially increased the amount of time for construction of the system and further substantially reduce the versatility of the system. In other words, there was no automatic connection or semi-automatic type connection between the struts and the connector nodes.
U.S. Pat. No. 2,868,568 to R. P. Frye discloses a connector referred to as a "knock-down structure" capable of being used as a nodal connector in a structural system. The Frye knock-down structure utilizes two pairs of similar plates and a pair of third plates which are dis-similar to the first two pairs. Thus, Frye cannot construct a node from all commonly sized and shaped plates or brackets. Frye must flex struts to enable connection to a node which inherently affects the rigidity of the system. Further, there is nothing to prevent rotation of a strut when connected to a node.
U.S. Pat. No. 4,308,698 to Gregg R. Fleishman also discloses nodal connectors or joints and a means for connecting struts to those joints by utilizing a unique interlocking arrangement between the joint and the strut. However, each joint is comprised of a single plate and struts are effectively connected in the single plate. Further, the plates and joints are connected to form a space enclosing geodesic dome like structure as opposed to as space frame structure.
U.S. Pat. No. 4,065,220 to Wayne Ruga also discloses a structural system utilizing tubular struts and a joint or a nodal connector. In this case, the tubular struts are adapated to fit into slots formed in the joint or node. However, Ruga must provide a large assortment of brackets and select from this large assortment of brackets to form a plurality of different node constructions. Also, there is no fastening means provided for locking the assembled components in the assembled relationship.